OS X: Snow leopard - assign application to a specific desktop

I find myself working more and more with fullscreen applications on OS X and use the 4 finger gesture to switch between them. Some applications don't let themselves use in this mode and used to overlay all other applications.

Then you start again thinking, wouldn't it be nice to always have that application on it's on desktop, where you can just switch over?

Using missing control move the application to the desktop (drag and drop) of choice and then select the application from the dock and right click->Options->Assign to This Desktop and you're done.